In European Patent Specification No: 92,408 B1, there is described an ear tag comprising a first button having an aperture, a pin having a head and a heel and being attached to the first button via engagement of the heel in the aperture prior to application of the tag to an animal, and a second button which is separate from the pin prior to application of the tag, the second button having an aperture in which the head of the pin is engaged on application of the tag.
On the prior tag, the buttons are of flexible plastics material, whereas the pin is of rigid plastics material. These material choices enable the tag to be readily applied to an animal's ear, and yet enable the tag to resist snagging in fences, gates etc., as can happen with tags of all rigid material. However, the prior tag and indeed other prior tags can on occasion be torn apart for illicit retagging of animals with the wrong tags.